$(3-91i)+(67)=$ Express your answer in the form $(a+bi)$.
Background Complex numbers can be added or subtracted by separately adding or subtracting their real and imaginary terms. To add or subtract complex numbers: Expand parentheses (attending to minus signs outside of parentheses if necessary) Combine all real terms (terms that do not contain $i$ ), and add or subtract them. Combine all imaginary terms (terms that contain $i$ ), and add or subtract them. Combining Like Terms $\begin{aligned} ({3}{-91}i)+({67})&={3}{-91}i+{67} \\\\ &={3}+{67}{-91}i \\\\ &={70}{-91}i \end{aligned}$ Summary $({3}{-91}i)+({67})={70}{-91}i$